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This work continues the series of the quantitative measurements of the proteins encoded by different chromosomes in the blood plasma of a healthy person. Selected Reaction Monitoring with Stable Isotope-labeled peptide Standards (SRM SIS) and a gene-centric approach, which is the basis for the implementation of the international Chromosome-centric Human Proteome Project (C-HPP), were applied for the quantitative measurement of proteins in human blood plasma. Analyses were carried out in the frame of C-HPP for each protein-coding gene of the four human chromosomes: 18, 13, Y, and mitochondrial. Concentrations of proteins encoded by 667 genes were measured in 54 blood plasma samples of the volunteers, whose health conditions were consistent with requirements for astronauts. The gene list included 276, 329, 47, and 15 genes of chromosomes 18, 13, Y, and the mitochondrial chromosome, respectively. This paper does not make claims about the detection of missing proteins. Only 205 proteins (30.7%) were detected in the samples. Of them, 84, 106, 10, and 5 belonged to chromosomes 18, 13, and Y and the mitochondrial chromosome, respectively. Each detected protein was found in at least one of the samples analyzed. The SRM SIS raw data are available in the ProteomeXchange repository (PXD004374, PASS01192).

Quantitative proteomic analysis of 50 blood plasma samples of healthy volunteers who underwent a comprehensive medical examination and were found eligible for space flights was performed. As a result of directed mass spectrometric analysis, signals for 128 proteins, which accounted for nearly 40% of the total number of chromosome 13 gene products, were detected. The analysis of interindividual variation of concentrations of chromosome 13 proteins showed the presence of a pool comprising 41 proteins with a low variation (CV < 30%), which can potentially be used as biomarkers.

Group structure and cohesion along with their changes over time play an important role in the success of missions where crew members spend prolonged periods of time under conditions of isolation and confinement. Therefore, an objective system for unobtrusive monitoring of crew cohesion and possible individual stress reactions is of high interest. For this purpose, an experimental wireless group structure (WLGS) monitoring system integrated into a mobile psychophysiological system was developed. In the presented study the WLGS module was evaluated separately in six male subjects (27-38 years old) participating in a 520-day simulated mission to Mars. Two days per week, each crew member wore a small sensor that registered the presence and distance of the sensors either worn by the other subjects or strategically placed throughout the isolation facility. The registration between two sensors was on average 91.0% in accordance. A correspondence of 95.7% with the survey video on day 475 confirmed external reliability. An integrated score of the "crew relation time index" was calculated and analyzed over time. Correlation analyses of a sociometric questionnaire (r = .35-.55, p< .05) and an ethological group approach (r = .45-.66, p < 05) provided initial evidence of the method's validity as a measure of cohesion when taking behavioral and activity patterns into account (e.g. only including activity phases in the afternoon). This confirms our assumption that the registered amount of time spent together during free time is associated with the intensity of personal relationships.

In this study the effect of factors of hermetic chamber with modified gas medium on the hemostasis system is analyzed in order to estimate and to compare different diving breathing gases. The parameters characterizing pro-, anticoagulant as well as fibrinolytic components of hemostasis were determined using clotting, chromogenic and immunological methods. The applied exposure did not affect the activity and regulatory potential of hemostasis significantly; however, the nitrogen-oxygen and argon-oxygen diving gases have a different effect on the hemostasis functioning, especially in the recovery period.

The paper is devoted to the hemostasis studies in the course of long-term (520 d) isolation in an airtight chamber. Measured parameters included activated partial thromboplastin time (APTT), international normalized ratio (INR), thrombin time (TT); concentrations of fibrinogen (FBG), plasminogen (PG), Willebrand factor (WF), tissue factor pathway inhibitor (TFPI), and tissue plasminogen activator (TPA), thrombomodulin (TM); activities of the coagulation cascade factors (II, V, VII, X, VIII, IX, XI, XII), antithrombin III (ATIII), protein C (PC), C1-inhibitor (C1), α2-antiplasmin (AP), TPA and TFPI. The investigation revealed a diversity of changes in the plasma fibrinogen concentration, slower blood coagulation in the intrinsic pathway and the final stage, and a relative rise in the activities of ATIII and PC-inhibited factors. The rest parameters showed different trends.

In an experiment with space flight simulation, atomic emission spectral analysis with inductively coupled argon plasma was employed to measure iron, zinc, stable strontium and lithium in blood serum and its ultrafiltered fraction, and excretion with daily urine and hair. Monitoring of serum iron and its ultraviolet fraction showed good balance of these parameters in all periods of the experiment. Blood serum was found to contain exclusively iron bound with protein carriers. In the experiment, serum zinc was distinctively dependent on the nutrient status. Stable strontium excretion with daily urine can be a biological indicator of its homeostasis. The experiment factors had no effect on the lithium form in serum, i.e. lithium was invariably present in the ionized form and in quantities equal to ultrafiltered lithium in all blood samples in all periods of the experiment.

Behavioral health risks are among the most serious and difficult to mitigate risks of confinement in space craft during long-duration space exploration missions. We report on behavioral and psychological reactions of a multinational crew of 6 healthy males confined in a 550 m(3) chamber for 520 days during the first Earth-based, high-fidelity simulated mission to Mars. Rest-activity of crewmembers was objectively measured throughout the mission with wrist-worn actigraphs. Once weekly throughout the mission crewmembers completed the Beck Depression Inventory-II (BDI-II), Profile of Moods State short form (POMS), conflict questionnaire, the Psychomotor Vigilance Test (PVT-B), and series of visual analogue scales on stress and fatigue. We observed substantial inter-individual differences in the behavioral responses of crewmembers to the prolonged mission confinement and isolation. The crewmember with the highest average POMS total mood disturbance score throughout the mission also reported symptoms of depression in 93% of mission weeks, which reached mild-to-moderate levels in >10% of mission weeks. Conflicts with mission control were reported five times more often than conflicts among crewmembers. Two crewmembers who had the highest ratings of stress and physical exhaustion accounted for 85% of the perceived conflicts. One of them developed a persistent sleep onset insomnia with ratings of poor sleep quality, which resulted in chronic partial sleep deprivation, elevated ratings of daytime tiredness, and frequent deficits in behavioral alertness. Sleep-wake timing was altered in two other crewmembers, beginning in the first few months of the mission and persisting throughout. Two crewmembers showed neither behavioral disturbances nor reports of psychological distress during the 17-month period of mission confinement. These results highlight the importance of identifying behavioral, psychological, and biological markers of characteristics that predispose prospective crewmembers to both effective and ineffective behavioral reactions during the confinement of prolonged spaceflight, to inform crew selection, training, and individualized countermeasures.

The results of studying the system of osteoprotegerin/ receptor activator of nuclear factor kappa-B ligand (OPG/RANKL) in 22 cosmonauts after long-duration (124 to 199 days) ISS missions are presented. Immediately on return to 1 g, changes were observed in OPG and RANKL serum levels and the ability to produce unstimulated and stimulated PGA of peripheral blood mononuclear cells in vitro. Individual variability of these changes was noticed. Our findings suggest that the cytokine OPG/RANKL-system is involved in bone remodeling in members of long-duration space missions.

In experiment MARS-500 on remote space flight simulation, atomic emission spectral analysis with inductively coupled argon plasma was used to measure serum copper and its ultrafiltration fraction. It was shown that, in contrast to baseline data, the Cu serum level varied within the normal physiological boundaries throughout the entire simulation experiment. These variations were sync in all the serum samples. In several periods in the experiment reductions in serum Cu within the baseline range were equivalent to simultaneous reductions in ceruloplasmin. Amount of the free Cu (ultrafiltration) fraction, i.e. not bound to proteins in blood serum, was constant at all times. Since the simulation experiment is not a perfect analogy of space flight because of nonreproducibility of some factors, ionizing radiation specifically, we should take into consideration shifts in the serum copper balance caused by the action of space radiation on human organism. Radiation-induced imbalance is not only a marker of disturbed oxidase function of blood but also points to a mechanism of potential pathological outcome of toxic excessive copper accumulated in the brain, liver and kidney.

In an experiment with 7-d dry immersion for testing the mechanic foot and electrical muscle stimulation procedures of compensating the support load deficiency the following biochemical parameters were studied: activated partial thromboplastin time, prothrombin time, prothrombin index, international normalized ratio, thrombin time (TT), fibrinogen, soluble fibrin-monomer complexes, D-dimer (DD), plasminogen (PG); antithrombin III activity (ATIII), protein C (PC) and alpha2-antiplasmin (AP). Control subjects (immersed w/o stimulation) did not exhibit significant shifts in the hemostasis system: however, they decreased ATIII, PC and PG in the post-experimental period. Mechanic foot stimulation did not have a noteworthy effect on the hemostasis system functioning during immersion, whereas electromyostimulation increased procoagulant and fibrinolytic activity in blood plasma.

The paper deals with the results of the effects of 520-day isolation and confinement modeling some elements of a mission to Mars on the immune system. Longitudinal analyses revealed that the mechanisms of adaptive response of the human immune system to the conditions of extremely long isolation led to a change of the parameters, characterizing innate and adaptive immunity. Among them the most important are: changes in the signaling PRRs--TLR, manifested in the reduction of the percentage of circulating monocytes and granulocytes expressed on its own surfaces TLR2, TLR4 and TLR6, decreases early NK cell activation potential, increases in the percentage T- and B-lymphocytes, that expressed early activation marker CD69 after adequate stimulation, and in production of cytokines in response to PHA stimulation. The active mobilization of the mechanisms of adaptive immunity, the implementation of the function of the level of immunity to a qualitatively different level, apparently, should be taken as a sign of adaptive adjustment of an organism in response to the complex influence of unfavorable factors, aimed at the preservation of immune homeostasis.

In the 520-d chamber experiment within the international project Mars-500 blood samples of 6 male test-subjects of 28 to 39 years of age were analyzed for water-soluble antioxidants: total bilirubin and uric acid; in addition, total antioxidant capacity of blood plasma was determined. Maximal values of these parameters were associated with the most stressful periods of the experiment, i.e. adaptation to the life in isolation and confinement, simulation of the egress onto Martian surface, and change of the diet. On attainment of the homeostatic equilibrium the parameters stabilized on levels slightly lower relative to baseline (pre-isolation) values. Therefore, dynamics of the water-soluble antioxidants reflected adequately the homeostatic reactions to and compensation by organism of the effects of the 520-day life in isolation and confinement.

Within the period of 2000 to 2012 the values of 40 diagnostically significant biochemical indices in venous blood were being determined during the pre-flight clinical and physiological examination of 28 Russian cosmonauts aged 35 to 54, members of main and back-up crews of expeditions to the International Space Station. The above examination was conducted 45-30 days prior to the launch. Taking account of the fact that each of the most of the cosmonauts performed several flights over the mentioned period and they were repeatedly included in back-up crews over and over again, each of cosmonauts participated in pre-flight examinations 1 to 5 times. Reference values were calculated for each of the studied indices. It was found that reference interval boundaries for 15 indices were narrower as compared to the generally accepted ranges. The upper boundaries of activity reference ranges of a number of enzymes, as well as of concentration of some metabolites of energy and plasticity metabolism were raised relative to mean population values. Thus, it was found that Russian cosmonauts being a specific professional team featured inherent reference values which differed from mean population values in a number of blood biochemical indices. It is conditioned by peculiarities of selection, physical training and psychic and emotional status of crew members during a pre-flight period.

The success of interplanetary human spaceflight will depend on many factors, including the behavioral activity levels, sleep, and circadian timing of crews exposed to prolonged microgravity and confinement. To address the effects of the latter, we used a high-fidelity ground simulation of a Mars mission to objectively track sleep-wake dynamics in a multinational crew of six during 520 d of confined isolation. Measurements included continuous recordings of wrist actigraphy and light exposure (4.396 million min) and weekly computer-based neurobehavioral assessments (n = 888) to identify changes in the crew's activity levels, sleep quantity and quality, sleep-wake periodicity, vigilance performance, and workload throughout the record-long 17 mo of mission confinement. Actigraphy revealed that crew sedentariness increased across the mission as evident in decreased waking movement (i.e., hypokinesis) and increased sleep and rest times. Light exposure decreased during the mission. The majority of crewmembers also experienced one or more disturbances of sleep quality, vigilance deficits, or altered sleep-wake periodicity and timing, suggesting inadequate circadian entrainment. The results point to the need to identify markers of differential vulnerability to hypokinesis and sleep-wake changes during the prolonged isolation of exploration spaceflight and the need to ensure maintenance of circadian entrainment, sleep quantity and quality, and optimal activity levels during exploration missions. Therefore, successful adaptation to such missions will require crew to transit in spacecraft and live in surface habitats that instantiate aspects of Earth's geophysical signals (appropriately timed light exposure, food intake, exercise) required for temporal organization and maintenance of human behavior.

In the course of a 3-day "dry" immersion experiment involving participation of five male test volunteers aged 25 to 40, in the blood serum of participants were determined the content of LPO (lipid peroxidation) products, namely diene conjugates, malon dialdehyde, shiffbases, as well as the values of the antioxidant protection system (AOP) indices - the concentration of tocopherol as the main lipid antioxidant and the level of general antioxidant activity. During the immersion action no deviations of indices under study from the background values were revealed, with the exception of a certain increase in tocopherol concentration within two hours after experiment beginning. At the restoring period after two hours upon immersion completion a reliable increase of lipid peroxidation products, particularly diene conjugates in participants' blood serum was made evident. At this, the tocopherol content was significantly below the background values. It is therefore concluded that the test participants' adaptation to the simulated weightlessness conditions shows no pronounced stress component, whereas bringing back to normal vital functions after exposure to immersion occurs with significantly pronounced stress reaction development, as demonstrated by considerable growth of LPO processes against the background of AOP system functional activity reducing.

Total and ionized magnesium in blood serum and in daily urine were determined before (baseline values) and on days 30, 60 and 105 of the experiment with 105-d isolation and confinement (Mars-105)/ Magnesium in hair was investigated before (baseline values) and on day-105 of the experiment. The investigations were performed using atomic emission spectrometry with inductively coupled argon plasma. Changes in magnesium were most significant over the initial 30 days in the experiment. Reduction of serum magnesium was accounted for by the fall in the ionized fraction. In organism magnesium is controlled by the ion-regulatory function of the kidney and varies with individuals. Levels of ionized magnesium in blood serum and excreted with daily urine can serve as indicators of stress resistivity .

Blood of six normal male volunteers sampled before, immediately after and in 7 days since 5-d dry immersion was analyzed for morphological parameters, erythrocyte metabolism, lipids and phospholipids levels. The experimental exposure was shown to increase the erythrocyte count. Also, upward trends were displayed by hemoglobin and PCV on the first day after the experiment; a significant decrease in adenosine triphosphate and low level of reduced glutathione could be an outcome of enhanced oxidation in cell due to, maybe, LPO activation. There was a downward trend in the phospholipids fraction of erythrocyte membrane against steady levels of cholesterol and its ethers which might be linked with the reliable growth of the fraction of nonesterified fatty acids on day 1 and triglycerides on days 1 and 7 post the experiment.

Relationships of the T- and B-components of adaptive immunity and the psychophysiological status were studied in 14 volunteers for the experiment with 5-d dry immersion (DI) w/o countermeasures. Comparison of frequency of deviations in immunity parameters of psychologically different subjects demonstrated the highest frequency in non-anxious and extravert individuals on day-5 in DI. These differences in immune reactions as a function of psychological type and temperament point to existence of a neuroimmune typology and, therefore, the necessity of concurrent immunologic and psychological investigations in order to develop separate measures of rehabilitation from and prevention of stress in people with polar psychological status.

Metabolic effects of physical countermeasures against deficient weight-loading were studied in three groups of 21-30 y.o. volunteers for 7-d dry immersion. Blood serum was investigated for 38 biochemical parameters that characterize myocardium, skeletal musculature, hepatobiliary system, kidney, pancreas, GI tract, prostate, and protein-nucleic, carbohydrate, electrolyte and mineral metabolism. Seven-day DI w/o countermeasures (n = 5) increased concentration of conjugated bilirubin, suppressed activities of muscular (creatine phosphokinase MM) and myocardial enzymes (CPK MB, OBDH), and caused an upward trend in cholesterol, its atherogenic LDP fraction and triglycerides. Mechanic sole stimulation (n = 6) intensified, within the physiological norm, erythrocyte hematolysis raising total bilirubin and potassium. Despite the stimulation, activity of muscle and myocardial enzymes made a decrease. Blood creatinine decreased to a less extent than in the immersed group w/o stimulation, however, lipid parameters did not rise. High-frequency stimulation of the lower leg and hip muscles in the course of immersion (n = 5) was noted to heighten the activity of muscle enzymes and potassium level in blood beyond the physiological norm. Change in creatinine did not reach a statistical significance and lipid metabolism parameters were not different from baseline values. Application of these physical methods of counteracting deficiency of weight bearing did not interfere with redistribution of body liquids due to immersion. Values of the parameters under study were mostly within the normal limits throughout the experimental exposure suggesting absence of pathological developments during DI or in consequence of physical stimulation. Therefore, the reactions were obviously of normal adaptive character.

In the blood serum of seventeen members of crews which participated in 14 orbital expeditions to the International Space Station with the duration of 125 to 217 days, during the pre-flight period and on the day of landing on the 1st, 7th and 14th days of the rehabilitation period (RP) the content of LPO products was determined, namely diene conjugates (DC), malon dialdehyde (MDA), shiffbases (SB) and the main lipid oxidant - tocopherol (TP). The group of astronauts who made landing in the Space Shuttle spacecraft (8 persons) and the group of astronauts who accomplished space mission in the Soyus TM spacecraft (9 persons) demonstrated a decrease in DC and MDA levels with a rise in TF concentration in the course of the rehabilitation period. Changes in the group of the American spacecraft astronauts were more pronounced. LPO inhibition during the rehabilitation period is recognized [treated] as an adequate reaction to the stress caused by re-adaptation to the ground conditions. Also are discussed probable mechanisms of intergroup differencies in LPO intensity degree: biomembrane phase state changing under the influence of overloads during de-orbiting and stress response intensity during landing in different types of spacecraft.

Six male volunteers (aged 25 to 40 years) were subjects in all-round psychophysiological, hormonal and immunological studies before, in and after 105-day isolation and confinement. Blood was drawn and the 16-factorial Cattell personality inventory was filled out every 30 days. Concentrations of blood hormones, neurospecific proteins and cytokines point to a close interrelation between antibody titers to myelin-associated glycoprotein and changes in the parameters of metabolism and reproduction-related hormones, as well as cytokines and individual psychophysiology (extra-introversion, dominance, intropunitiveness, social contact selectivity, etc.), and suggest a minimum risk of demyelinizing neuropathy due to exposure to the conditions of isolation and confinement.

The system of congenital immunity was studied in 12 essentially healthy males 18 to 26 years of age subjected to 5-day dry immersion without use of countermeasures. Peripheral blood was analyzed for monocytes, granulocytes and lymphocytes expressing the TLR2+, TLR4+, TLR6+, CD11b+, CD14+, CD16+, CD18+, CD24+, CD36+, CD54+, CD56+ and CD206+ receptors. Expression of early activation marker CD69 on lymphocytes-natural killers was studied in unstimulated and interleukin-2 activated mononuclear cell cultures. The negative shifts in the congenital immunity system in some volunteers at the end of immersion and during recovery can be considered as warnings about depletion of the system reserve and increase of the risk of infectious diseases such as caused by normal microflora which typically does not provoke pathological reactions of the host.

The present paper deals with studying of hemostasis system indices in the course of the experiment with a 105-day isolation in a hermo chamber. The following values were determined: activated partial thromboplastin time, prothrombin time (PT), prothrombin index (PI), international normalized ratio [relationship] (INR), thrombin time, fibrinogen concentration, soluble fibrin-monomer complexes, D-dimer, plasminogen (PG), activity of antithrombin III, protein C, alpha2-antiplasmin. According to the experiment results, isolation is accompanied by PT prolongation (PI decreasing, INR increasing) which conserves up to the 7th day of the aftereffect period, as well as by PG concentration decreasing. Changes are likely to be connected with peculiarities of reduced motion activity conditions, compensatory physical activity influence, protein and lipid metabolism characteristics changing.

Comparison of bone mineral density and fatty-acid blood content in 9 human subjects exposed to 370-d bed rest revealed correlation of the loss in femoral neck density with parameters of lipid exchange. On day-46 of BR, the absolute lipids content in erythrocyte membranes and blood serum decreased considerably (1.5-2 times) when compared with baseline data. At the end of the experiment, lipids content in serum, on the contrary, surpassed baseline values 2-3 times: however, it remained lowered in erythrocyte membranes of the control group till day-280 of BR. Arachidonic acid correlated with prostaglandins PGE2 and PGF2alpha involved in regulation of osteoclasts and osteoblasts activities. Correlation of decreases in femoral neck density and unsaturated fatty acids in blood serum and erythrocyte membranes varied with the human subjects.

Before, in and after the experiment with 105-day isolation and confinement, 6 male volunteers from 25 to 40 years of age rationed NaCl and performed integral impedancimetric, psychological and hormonal investigations. Every 30 days blood collection for hormonal measurements was combined with filling of Cattell's 16 personal factor questionnaire. Parameters of total body fluid, body mass, basic exchange, specific hydration and basic exchange were determined. The results showed that the experimental conditions did not affect significantly body composition, metabolism or neurohumoral regulation; the metabolic variations were largely associated with motivation for and value orientation in accommodation, to the permissible extent, of the controlled diet and work/rest schedule to personal needs. In addition, it was found that evolution of the psychophysiological status of humans in isolation and confinement is governed primnarily by personality characteristics and, to a less degree, specifics and length of exposure to the artificial environment; thus, in the opinion of the volunteers normoxic, normobaric and slightly hypercapnic (0.15-0.65% CO2) atmosphere was comfortable and harmless to health. Analysis of the whole data array verified the expressed interrelation of neuroendocrine and psychophysiological parameters as well as shifts in body basic exchange and mass, salt intake and hydration rate in the conditions of isolation and confinement.

Effects of strict 105-d isolation on blood antioxidant status, erythrocyte membrane processes and oxygen-binding properties of hemoglobin were studied in 6 male volunteers (25 to 40 y.o.) in ground-based simulation of a mission to Mars (experiment Mars-105). The parameters were measured using venous blood samples collected during BDC, on days 35, 70 and 105 of the experiment and on days 7 and 14-15 after its completion. Methods of biochemistry (determination of enzyme activity and thin-layer chromatography) and biophysical (laser interference microscopy, Raman spectroscopy) showed changes in relative content of lipid and phospholipid fractions suggesting growth of membrane microviscosity and increase in TBA-AP (active products of lipids peroxidation interacting with thiobarbituric acid). A significant increase in glucose-6-phosphate dehydrogenase and superoxide dismutase activities against reduction of catalase activity points to both reparative processes in erythrocytes and disbalance between the number of evolving active forms of oxygen and antioxidant protection mechanisms in cells. Hemoglobin sensitivity of oxygen and blood level of oxyhemoglobin were found to increase, too. It is presumed that adaptation of organism to stresses experienced during and after the experiment may destroy balance of the antioxidant protection systems which is conducive to oxidation of membrane phospholipids, alteration of their content, increase of membrane microviscosity and eventual failure of the gas-exchange function of erythrocytes.

The present paper deals with studying ofhemostasis system indices after short-term (10-11 days) space flights as well as in the course of the experiment with a 7-day "dry" immersion. The following values were determined: activated partial thromboplastin time, prothrombin time, prothrombin index, international normalized ratio (INR), thrombin time (TT); fibrinogen, soluble fibrin-monomer complexes, D-dimer, plasminogen (PG) concentration; activity of antithrombin III (ATIII), protein C (PC), alpha2-antiplasmin (AP). In the 1st day after space flights a fibrinogen concentration was increased significantly as well as TT shortening tendency and fibrinolysis activation tendency were observed. There were no significant changes in ATI I11 and PC activities. During the immersion period there were no significant changes in investigated indices, with the exception of AP activity increase in 3rd day of experiment. In readaptation period, however, a decrease in ATIII and PC activities as well as PG concentration was observed. Hemostasis system response features after space flights and during immersion are probably due to different intensity and duration of external factors effects.

Healthy volunteers' bone system investigation was performed before and after 105 days experiment in an isolated environment (MARS-105) using dual energy X-ray absorptiometry (DXA) and peripheral quantitative computed tomography (pQCT). Volumetric bone mineral density (VBMD), bone mineral density (BMD), structural parameters of radius and tibia were evaluated. There were no significant BMD changes revealed in skeletal parts critical in terms of biomechanical properties. pQCT examination noted microarchitecture deterioration of radius that was reflected in decreasing of trabecular number and increasing of bone tissue inhomogeneity. Decreasing VBMD both cortical and trabecular bone were revealed for tibia. Unexpectedly, increasing oftrabecular number and decreasing of inhomogeneity were revealed for tibia. Experiment showed that only the complex investigation including DXA and pQCT measurements gives an idea about bone system changes under simulated experiment conditions.

Microgravity effect on bone tissue of cosmonauts was evaluated following space flights of 6 months in duration. Peripheral quantitative computed tomography (pQCT) was used to determine volumetric bone mineral density (VBMD) and structure of distal parts of the leg and forearm. Changes in VBMD were found to correlate with bone position relative to the vector of gravity. In the forearm, reversible hypermineralization was bound together with compact bone thickening. Reversible osteopenia in the lower leg was accompanied with plausible losses both in compact and trabecular bone. Irrespective of position relative to the vector of gravity, bone microarchitecture tended to reduce the number of trabecules and to increase heterogeneity of the trabecular network. Pre-flight structural dynamics showed a complex character with linear time dependence.

Biochemical investigations of red blood and oxygen transportation by erythrocyte hemoglobin were performed in volunteered for chamber experiments (0.14 MPa) with normal and hypoxic oxyargon medium (O2-Ar). Erythrocyte metabolism, lipid and phospholipids spectra, and effectiveness of oxygen release and retention by hemoglobin were studied in the baseline data collection period, on day 6 in hyperbaric and normoxic O2-Ar medium (13.7% O2), on day 3 in hyperbaric and hypoxic O2-Ar (9.9% O2) and on day 1 and 10 during the post-experiment rehab. Elevated pressure, hypoxia and ensuing decompression revealed an ATP reduction that could be a result of shifts on the membrane level and increased G6PD activity associated with cell reparation processes. Changes in membrane lipid and phospholipids composition point to an altered phase state of plasmatic membrane, i.e., increased viscosity which is indicative of possible impairment of membrane permeability As a rule, hyperbaria impacted oxygen transportation in blood of the subjects; effect of hypoxia combined with hyperbaria was not uniform ranging from none to decreasing or increasing oxygen transportation that can be extenuated by selectivity and individual sensitivity to the factors in the experiment Loss of O2 transportation efficiency by hemoglobin is most likely connected with the increase of plasmatic membrane viscosity that could affect hemoporphyrin conformation of membrane-bound hemoglobin and obstruct oxygen transport though membrane.

Eight volunteered male test-subjects (20-40 y.o.) took part in an experiment with 21-hr bed rest aimed to investigate trends in the hemostasis parameters (activated partial thromboplastin time, prothrombin time, thrombin time, fibrinogen, plasminogen, D-dimers, soluble fibrin-monomer complexes (SFMC), as well as antithrombin III (ATIII) and protein C (antiplasmin) activities) after diuretics-induced dehydration followed by intravenous infusion of colloid and crystalloid solutions. It was shown that noncompensible dehydration during bed rest does not lead to noteworthy alterations in the procoagulating component of hemostasis. Intravenous infusion of blood substituting sterofundin (crystalloid) and venofundin (colloid) to the bedrested human subjects accelerated coagulation within the physiological norm. In all series of the experiment ATIII was suppressed and plasminogen content went down causing growth in SFMC. Fibrinogen concentration remained essentially unchanged pointing to the absence of acute reaction of organism to the experimental conditions.

Subpopulations of lymphocytes, activation potential of T-, B- and NK-cells as well as cytokines production by immunocompetent cells in peripheral blood were studied in five volunteers for 7-day dry immersion without use of countermeasures. Results of the investigation revealed several negative shifts in the immunity and cytokines systems instigated by the experimental conditions. The considerable variability of the immune reactions to immersion suggests individual predisposition to immunological breaks in a changed gravity environment.

The investigation into the immune effects of 9-d exposure to elevated pressures of normoxic and hypoxic O2-N-Ar atmosphere showed changes in a number of indices of genetic and adaptive immunity in normal humans. Dynamics and depth of the functional shifts under the influence of the experimental factors appear to be connected with genetically coded mechanisms of immunoreactivity. Monitoring of immune homeostasis is basic to the prevention of immune adaptation failure.

Morphobiochemistry of erythrocytes, erythropoiesis intensity (determined by iron metabolism and erythropoietin content), lipids and phospholipids of erythrocyte plasmatic membrane and oxygen binding and release by hemoglobin were studied in normal male volunteers for 7-d dry immersion. Investigations were performed before the experiment, on the last day in immersion (d-7) and on days 7 and 15 of recovery. After 7-d dry immersion, the volunteers exhibited a trend towards changes in red blood morphology, erythropoiesis intensity, and erythrocyte metabolism. Seven-day simulation of microgravity alters significantly the oxygen-transporting function of erythrocytes. This is, probably, associated with shifts in the cell membrane evidenced by apparent changes in phospholipids fractions. These changes have no clinical significance as concluded from reestablishment of most of the parameters by day 15 of recovery. The broad variability of measured values is attributed to individual character of body response to the stresses of the experiment.

Blood samples were taken from 8 volunteers (21 to 26 years of age) for 7-day immersion 7 days prior to, on days 3 and 7 of the experiment and on days 1 and 8 of recovery. Serum was analyzed for 38 biochemical markers of the functional state of the myocardium, skeletal muscles, hepatobiliary system, kidney, pancreas, GI tract, prostate, and protein-nucleic, carbohydrate, electrolyte and mineral metabolism. Seven-day immersion was found to alter the biochemical parameters within the physiological norm boundaries. The observed changes included lower activities of enzymes associated with muscular and myocardial constellation, shifts in electrolytes (K, Na, Mg), and increases in the biliary function parameters. Increased concentrations of the lipid metabolism parameters suggest a higher risk of atherogenesis. Biochemical parameters of bone tissues and erythrocyte activity were essentially unchanged. Most of the parameters returned to pre-experimental values by day 8 of recovery.

In an experiment with 7-d immersion of 8 male test-subjects (21-26 y.o.) we investigated excretion with urine of total protein, creatinine, urea, uric acid, glucose, K, Na, Ca, P, Mg, 12 groups of proteins and 5 enzymes. Results of the investigation bring to the conclusion that 7-d immersion does not impact the kidney functioning. Analysis of uroproteinogram failed to detect shifts in glomerular filtration or tubular reabsorption which correlates with the absence of significant changes in uroenzymogram. Even profuse diuresis was unable to provoke abnormally high protein and glucose excretion, whereas electrolyte excretion normalized fairly soon. Increased excretion of creatinine, urea, Ca, Mg and P appears to reflect activation of catabolism in skeletal muscles.

Genome dose of active ribosome genes (ARG), average of nucleolus argyrophil structures in lymphocyte nuclei, levels of extracellular DNA (DNA(e)) concentrations and ratio of antibodies to total DNA (AB(DNA)) and ribosomal DNA (AB(DNA-rib)), and nuclease activity were determined in peripheral blood of 8 volunteered subjects (21-26 y.o.) in the experiment with 7-d DI. Results of the investigation revealed a broad individual variability ensued from heterogeneity of the group of the test-subjects as to ARG values. There was an inverse negative relationship between ARG values and increment of the ribosome genes activity index. Part of the subjected exhibited increased DNA(e) levels on completion of the experiment, whereas the others decreased the parameter demonstrating individual character of body reaction. No correlation was established between DNA(e) content and nuclease activity in blood. Concentrations of AB(DNA) and DNA AB(DNA-rib) before and after immersion were essentially unchanged; however, they were higher as compared with the control group of blood-donors. Diversity of subjects' reactions was accounted to the broad range of ARG values. Therefore, selection of test-subjects for ground-based simulation experiments should be conducted with due consideration of the parameter.

Morphobiochemical investigations of red blood (space experiment Hematologiya) involved the ISS Russian crew members (increments 6-12). Blood samples were drawn on L-30, at the beginning (FD 6-10) and end (FD 160-190) of orbital flight, shortly after landing (R+0), and on R+7 and R+15. Results of the investigations of red blood metabolism and cell membrane showed that long-duration space flight reduces the hemoglobin level in consequence of, probably, intensive erythropoiesis and premature partial elimination of degraded (possibly old) erythrocytes from circulating blood. High intensity of erythropoises is manifested by an increase in erythropoietin, a decrease in blood iron, and elimination of degraded and old erythrocytes in the course of readaptation to Earth and driven by the growing body demand for oxygen to support muscular work and existence in the gravitational environment in general.

Plasmatic membrane viscosity and permeability and hemoporphyrine conformation in human hemoglobin were studied on completion of long-duration space flight (LSF). Reversible increases in viscosity and selective permeability (Na+/H+ -turnover) of erythrocyte plasmatic membrane were observed immediately after and in the period of recovery from LSF. Viscosity of lipids in both external and internal locations of plasmatic membrane in human erythrocytes was changed after LSF. The reversible rise of the Na+/H+ -turnover is likely to alter intracellular pH and oxygen binding with hemoglobin. The former is confirmed by the concurrent reversible decline in the deoxyhemoglobin ability to bind oxygen and the oxyhemoglobin ability to retain oxygen. In LSF and during readaptation to the normal gravity blood levels of hemoglobin and free iron are known to be reduced and may be answerable for the hypoxic state of human organism.

According to the experiment Hematology protocol, blood samples from the Russian members of ISS prime crews 1 to 5 were gathered on L-30 and R+0, 7, 15 to study metabolic parameters (ATP, reduced glutathione, LHG and glucose-6-phosphate dehydrogenase activities). Lipid spectrum of membrane erythrocytes was determined in frozen erythrocyte mass; iron turnover and erythropoietin were investigated in frozen serum. Ratios of different erythrocyte forms were established in 32 microl of fixated whole blood using scanning electron microscopy. On R+0, the morpho-biochemical parameters of red blood appear to still carry the imprints of space effects and, to an extent, certain difference in the setting of blood sampling from the Mir crew on landing in the space "shuttle" vehicle. Low level of iron and significantly increased erythropoietin on R+0 are the testimony of intensive hemoglobin production and an adequate bone morrow response to the increased oxygen demand. Shifts in erythron are of no clinical implications but indicative of the red blood adaptation to the factors of space fight.

Confinement is one of the stress-inducing factors which humans face in such terrestrial environments as those in polar winter-over expeditions, submarines, and is inevitable in space flights. Confinement regime (CR) itself includes a number of stress factors (e.g. psychological compatibility between crew members, microbiological contamination etc.), which have been shown to alter human immunity. Two groups of total seven subjects spent 110 days in closed-habitat chamber as part of SFINCSS (Stimulation of Flight of International Crew on Space Station) study. Distribution of T-cell subsets, NK-, B-cells, and monocytes in whole blood was assessed. Secretion of type I (IL-2, IFN-gamma, TNF-beta) and type II (IL-4, IL-10) cytokines in the LPS/PHA activated whole blood cell culture was assessed. Significant alterations in type I / type II cytokine equilibrium were observed during and after confinement. The data show that stress factors associated with confinement may lead to disbalance between cell-mediated and humoral immune reactions.

Red blood was analyzed in six 25 to 40 yr. old male volunteers in a 120-d head-down bedrest (HDBR) study. The hematological investigation included morphological analyses (erythrocyte count and hemoglobin), and determination of iron turnover, erythrocyte IgA, IgG and IgM, metabolism, lipids and phospholipids, and lipid peroxidation rate (LPO). At the beginning of HDBR (day 7), the erythrocyte count and hemoglobin content were found increased w/o any visible changes in the other parameters. Further exposure to HDBR (days 50-100) resulted in modification of intracellular metabolism in erythrocytes, increases in serum iron, and serum and erythrocyte ferritin. On HDBR days 50 and 100, and post-HDBR day 9, cholesterol was increased, LPO intensified and antioxidant activities inhibited, which suggested destabilization of the cell membrane. Hematological shifts in the bedrested volunteers were of the type and pattern similar to those in cosmonauts who fulfilled extended space missions.

Serum calcium and serum and erythrocyte higher fatty acids (HFA) in 8 male subjects in a 370-d head-down bed rest experiment were different in group-A (applying preventive physical training and pharmacy) and group-B (control). On day 46 of the experiment, HFA content in all lipid fractions decreased sharply in both groups; however, HFA level in serum exceeded baseline values in 2-6 times and remained low in erythrocytes. Difference between the groups became appreciable on HDT day 110.

Introduction: Static bone histomorphometry was applied to existing iliac bone sections originating from a 370-d 5 degrees head-down bed rest experiment. This bed rest experiment is the longest ever to have been conducted. We hypothesized that bed rest would decrease cancellous bone volume fraction and that this effect would be reversed by countermeasures., Methods: Eight healthy male subjects underwent 370 d of 5 degrees head-down bed rest. Three subjects were treated with bisphosphonate (Xidifon, potassium salt of ethane-1-hydroxy-1-disphosphonate, EHDP) combined with an exercise regimen (1-2 h x d(-1)) for the entire study period. Five subjects underwent 120 d of bed rest without countermeasures followed by 250 d of bed rest with the exercise regimen. Transiliac bone biopsies were obtained either at baseline and day 366, or at baseline, day 116, and day 366 at alternating sides of the ileum. Static histomorphometry was performed using a computerized method., Results: The 120 d of head-down bed rest without countermeasures resulted in decreased bone volume fraction BV/TV (-6.3%, p = 0.046) and trabecular number (Tb.N; -10.2%, p = 0.080) and increased trabecular separation (Tb.Sp; 14.7%, p = 0.020), whereas the 250 d of subsequent head-down bed rest with exercise treatment prevented further significant deterioration of the histomorphometric measures., Discussion: The 120 d of 5 degrees head-down bed rest without countermeasures induced significant deterioration of iliac crest cancellous bone histomorphometric properties. On average, the countermeasures consisting of either bisphosphonate and exercise, or exercise alone were able to either prevent or stop immobilization-induced changes of the iliac cancellous bone structure.

In eight Russian members of the ISS crews 1 to 5 enzymes and some other metabolites were analyzed in blood in the pre- launch period, on the landing day, and on days 6-8 and 14-19 of recovery. Deviations in the biochemical parameters were typically within the physiological norm without clinical implications. Biochemical deviations on the landing day seemed to relate to metabolic shifts due to long-term microgravity and, on the other hand, were a reaction to acute gravitational stress on return to 1 g. Dynamics of a number of parameters was markedly different as compared with the data from cosmonauts who had made long missions to the Mir space station, but this can be attributed to different g-profiles during descent and blood sampling schedule. In two to three wks the parameters regained normal values suggesting that negative effects of readaptation to the Earth's gravity were fully remedied.